1. Field
Example embodiments relate to an organic insulator composition including a hydroxyl group-containing polymer and a dielectric film and an organic thin film transistor (OTFT) using the same. Other example embodiments relate to an organic insulator composition, which includes a crosslinking agent and a hydroxyl group-containing oligomer or hydroxyl group-containing polymer, that may be used to form a thin film using a low-temperature wet process.
2. Description of the Related Art
In general, a thin film transistor (TFT) is used as a switching device for a flat panel display example (e.g., a liquid crystal display, an organic electroluminescent display, an electrophoretic display or the like). A semiconductor layer of the TFT is generally formed of an inorganic semiconductor material (e.g., silicon (Si)).
According to the recent trend toward the fabrication of large, inexpensive and flexible displays, research is being conducted on organic semiconductor materials that may replace expensive inorganic materials that require a high-temperature vacuum process. Because an organic thin film transistor (OTFT) may be fabricated using a solution process at low temperatures, it may be easier to apply the OTFT to large-area flat panel displays, which are fabricated using only a deposition process. The OTFT may be prepared in the form of a fiber or a film due to the properties of the organic material. As such, an OTFT may be used in a flexible display device.
The flexible display device may be formed on a thin and flexible substrate (e.g., paper). The flexible display device may have increased flexibility (including bendability and windability) and/or a higher resistance to damage and impact.
During the fabrication of a flexible display device, an organic insulator may be formed into a thin film on a plastic substrate and cured by performing a curing process (e.g., thermal curing).
Thermal curing may be performed at a substantially high temperature of 150° C. and above. Because of the substantially high temperature, thermal deformation of the plastic substrate may occur during the insulator curing process, leading to misalignment. As such, electrical properties of the device may deteriorate.
Research on novel organic gate insulating films, which may be subjected to a low-temperature process to decrease negative influences on the substrate or other process films, is being conducted. Although the organic insulating film (e.g., polyimide, polyvinylalcohol, poly(vinylphenol-maleimide), or photoacryl) is used, it may not increase the properties of the device to the extent that it can be considered a comparable alternative to conventional inorganic insulating films.
In order to form OTFTs having higher efficiency, alternative materials for the insulating film that exhibit heat and/or chemical resistance are being researched, enabling the formation of a thin film through a wet process at a temperature lower than 130° C. Alternative materials for the insulating film that increase electrical properties (including charge mobility, threshold voltage, and on/off current ratio) of a device when used in an OTFT are also being researched.